The present invention relates to the general field of telecommunications and in particular to communication via the Internet.
It relates more particularly to mechanisms for terminating a voice over IP (Internet Protocol) call sent or received by a terminal such as a telephone implementing the Session Initiation Protocol (SIP), for example. Such a terminal is also known as a voice over IP terminal or VoIP terminal.
In the current state of the art, when a voice over IP terminal hangs up, the resources allocated to the call at the terminal level and more generally in the network are released immediately and the call between the two parties is terminated definitively.
Consequently, if hanging up is linked to misoperation of the VoIP terminal, for example accidentally pressing the hang-up key of the terminal or accidentally dropping the handset of the terminal onto its base after picking it up, to resume the conversation the user of the VoIP terminal has no solution other than to call the other party again.
In standard time-division switching in public switched telephone networks (PSTN) there is a hang-up/repick-up mechanism that enables a called subscriber to hang up their telephone handset and then to pick up the same handset or another handset within some determined time interval without the call with the other party being cut off. The use of such a mechanism in a PSTN relies on call suspension messages exchanged between the subscriber connection unit and the autoswitch to which it is connected.
Because of the architecture and the design of voice over IP networks, voice over IP protocols do not include such exchanges. Consequently, any misoperation of a voice over IP terminal handset during a call inevitably leads at present to the resources associated with the call being released.